Thursday, July 2, 2015

New Horizons Spacecraft Detects Methane on Pluto, Reveals Two Distinct Faces of the Dwarf Planet

Pluto shows two remarkably different sides in these color images of the planet and its largest moon Charon taken by New Horizons on June 25 and June 27. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Yes, there is methane on Pluto, and, no, it doesn’t come from cows. The infrared spectrometer on NASA’s Pluto-bound New Horizons spacecraft has detected frozen methane on Pluto’s surface; Earth-based astronomers first observed the chemical compound on Pluto in 1976. “We already knew there was methane on Pluto, but these are our first detections,” said Will Grundy, the New Horizons Surface Composition team leader with the Lowell Observatory in Flagstaff, Arizona. “Soon we will know if there are differences in the presence of methane ice from one part of Pluto to another.”

Methane (chemical formula CH4) is an odorless, colorless gas that is present underground and in the atmosphere on Earth. On Pluto, methane may be primordial, inherited from the solar nebula from which the solar system formed 4.5 billion years ago. Methane was originally detected on Pluto’s surface by a team of ground-based astronomers led by New Horizons team member Dale Cruikshank, of NASA’s Ames Research Center, Mountain View, California.

New color images from NASA's New Horizons spacecraft show two very different faces of the mysterious dwarf planet, one with a series of intriguing spots along the equator that are evenly spaced. Each of the spots is about 300 miles in diameter, with a surface area that's roughly the size of the state of Missouri.

Scientists have yet to see anything quite like the dark spots; their presence has piqued the interest of the New Horizons science team, due to the remarkable consistency in their spacing and size. While the origin of the spots is a mystery for now, the answer may be revealed as the spacecraft continues its approach to the mysterious dwarf planet. "It's a real puzzle—we don't know what the spots are, and we can't wait to find out," said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder. "Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon."

New Horizons team members combined black-and-white images of Pluto and Charon from the spacecraft's Long-Range Reconnaissance Imager (LORRI) with lower-resolution color data from the Ralph instrument to produce these views. We see the planet and its largest moon in approximately true color, that is, the way they would appear if you were riding on the New Horizons spacecraft. About half of Pluto is imaged, which means features shown near the bottom of the dwarf planet are at approximately at the equatorial line.

If Pluto has clouds, New Horizons can detect them. Both the high-resolution LORRI imager and the Ralph color imager will be used to look for clouds across the face of Pluto during its approach and departure from the planet. "We're looking for clouds in our images using a number of techniques," said science team postdoc Kelsi Singer of the Southwest Research Institute, "If we find clouds, their presence will allow us to track the speeds and directions of Pluto's winds."

Credit: jhuapl.edu

No comments:

Post a Comment